Fuel oil composition

ABSTRACT

A diesel fuel composition comprising diesel fuel, triglycerides of vegetable origin and an oxygenate material exhibits good engine emissions, improved lubricity and no deterioration in engine performance.

FIELD OF THE INVENTION

The present invention relates to a diesel fuel composition which comprises fuel oil, triglycerides of a vegetable origin and an oxygenated material.

BACKGROUND OF THE INVENTION

The regulatory requirements of diesel fuels require specific emission controls in the production of sulfur, aromatic and acid groups during the combustion of the diesel fuels. To meet these emission standards, the industry has suggested several refining process techniques and treatments, such as catalytic hydrogenation, to refine the diesel fuels and to provide compliance with these regulatory requirements. The diesel fuels produced by these refining processes has resulted in the production of diesel fuels possessing low sulfur and low aromatic contents. However, such diesel fuels having low sulfur and low aromatic contents cause damage to the injection systems utilized with diesel engines.

In diesel engines the combustible mixture of air and fuel oil mixture is ignited by the high temperature generated during the compression of the air. Air is drawn into the cylinder during the downward stroke of the piston and compressed and heated on the upward stroke. The fuel oil is injected through the injector pump and the injector nozzles into the compressed cylinders. When diesel fuels having a low sulfur content are injected through these injector systems, the inability of such fuels to lubricate the injection systems of the diesel engine is substantially reduced, causing the fuel injection systems to become clogged and ineffective. In diesel systems, the diesel fuel itself is the lubricant for the injector systems. Thus, because the fuel is substantially free of any lubricating property the injection systems become clogged and ineffective. Thus, the ineffective lubricity of the low sulfur containing fuel oils has caused the petroleum industry to identify additive materials to solve this lubricity problem.

Although several additives have been proposed for use with fuel oil to improve the lubricity of the fuel oil, generally such additives when added to the fuel oil composition do not provide a diesel fuel suitable for combustion. For example, several types of aromatic, dimer/trimer acids and fatty acids have been added to fuel oils to provide lubricity to the fuel oil composition. However, such aromatic and acid materials generally cause gel formation in the fuel oil filters, which cause problems for such fuel oil injecting systems. Also, such additives do not provide sufficient low-temperature fluidity to solve the problem of lubricity of the injecting systems.

Additionally, the prior art has suggested also the use of amides, specific type ureas and epoxidized vegetable oils as an additive to fuel oil compositions to improve the lubricity of the fuel injecting systems. Moreover, the use of such additives have not provided a stable fuel composition because the chemical reactions used in their formation are reversible thereby causing a regeneration of the acids which cause gel formation of the fuel oil composition.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a novel diesel fuel composition which results in a reduction of engine emissions over commercial grades of diesel fuels.

Another object of the present invention is a fuel oil composition which possesses sufficient lubricity to properly lubricate the fuel injection systems of diesel engines.

Still another object of the present invention is a fuel composition containing an oxygenate material having a flash point of at least 38° C. and a pour point greater than 15° C.

The invention provides a diesel fuel composition comprising 50-99.9% by weight diesel fuel, 0.1-50% by weight of triglycerides of a vegetable oil and 0.1-25% by weight with respect to the weight concentration of triglycerides of the vegetable oil of an oxygenate material. The oxygenate material is present in the diesel fuel composition in an amount effective for the composition to exist as a stable solution. The fuel composition includes an oxygenate material to control and reduce the exhaust emissions from the diesel engine. The oxygenate material has a flash point of at least 38° C., a pour point greater than 15° C. and a solidification point of less than 20° C. The combined amounts of oxygenate and the triglycerides of the vegetable oil are sufficient to impart to the fuel composition a kinematic viscosity in the range of 1.5-4.1 centistokes at 40° C.

The diesel fuel composition in accordance with the present invention provides a lubricity to the fuel composition, and provides lower engine emissions while not adversely impacting the sulfur content of the low sulfur diesel fuel. Additionally, vehicle performance of the diesel fuel compositions in accordance with the present invention exhibit little deterioration in performance versus conventional diesel fuels.

The diesel fuel composition in accordance with the present invention comprises and shall be understood to mean a mixture of hydrocarbon that is the fraction of crude oil that distills after kerosene and is useful in combustion in diesel type or compression-ignition engines. This diesel fuel may include No. 1-D and No. 2-D grade diesel fuels, as designated by ASTM standards. Also, as is known in the art, diesel fuel may comprise atmospheric or vacuum distillate or blends thereof. The diesel fuels will have a cetane number greater than 40.

The utilization of triglycerides of a vegetable oil provides a diesel fuel composition which may be prepared from natural and renewable sources. The triglyceride of a vegetable oil is selected from a group comprising rapeseed oil, soybean oil, peanut oil, palm oil, palm kernel oil, coconut oil, tall oil, canola oil, linseed oil, corn oil, sesame oil, cottonseed oil, jatropha oil, crab oil, sunflower seed oil, safflower oil, oleo safflower oil, triolein and mixtures thereof.

The oxygenate material utilized in the present invention to facilitate oxidation of the fuel oil composition is preferably an alcohol selected from a group comprising n-butanol, n-hexanol, n-heptanol, n-octanol, n-nonanol or n-decanol.

The fuel oil composition in accordance with the present invention includes an oxygenate material ranging, preferably, between 0.1 to 30% by weight with respect to concentration of triglycerides of the vegetable oil. However, it is within the scope of the present invention that the preferred range of oxygenate material is between 0.1 to 25% by weight with respect to the weight of the triglycerides. The oxygenate is added to the fuel composition to control and limit the exhaust emissions from the combustion process of the fuel composition. The oxygenate material possesses a flash point or a minimum temperature that enables combustion to take place of at least 38° C., a pour point of at least 15° C., and a solidification of less than 20° C. The oxygenate material may be selected from a group comprising n-butanol, n-hexanol, n-heptanol, n-octanol, n-nonanol or n-decanol, a ketone such as 2-ocatanone and long chain fatty acid esters, such as, methyl cis-9-octadecenoate.

Further, in accordance with the present invention, the diesel fuel composition may further include and be comprised of 0.01-7% by weight with respect to the total weight of the concentration of triglycerides of a monocyclic terpene material. The preferred terpene material is limonene and is utilized in the present invention to facilitate dispersion of the fuel oil composition, to improve lubricity of the fuel and satisfy winterization of the fuel oil composition.

The diesel fuel composition in accordance with the present invention provides a renewable non-petroleum source of non-toxic materials for use in a diesel fuel composition. This renewable source provides lubricity, winterization protection, and controls pollutant emissions while maintaining engine performance.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a diesel fuel composition comprising 50-99.9% by weight diesel fuel, 0.1-50% by weight of triglycerides of a vegetable oil and 0.1-30% by weight with respect to the weight concentration of triglycerides of the vegetable oil of an oxygenate material. The oxygenate material is present in the diesel fuel composition in an amount effective for the composition to exist as a stable solution. Accordingly, it is within the scope of the present invention that the preferred range of oxygenate material is between 0.1 to 25% by weight with respect to the weight of the triglycerides. The fuel composition includes an oxygenate material to control and reduce the exhaust emissions from the diesel engine, lower viscosity and improve winterization properties. The oxygenate material has a flash point of at least 38° C., a pour point greater than 15° C. and a solidification point of less than 20° C. The combined amounts of oxygenate and the triglycerides of the vegetable oil are sufficient to impart to the fuel composition a kinematic viscosity in the range of 1.5-4.1 centistokes at 40° C.

The diesel fuel composition in accordance with the present invention provides a lubricity to the fuel composition, and provides lower engine emissions while not adversely impacting the sulfur content of the low sulfur diesel fuel. Additionally, vehicle performance of the diesel fuel compositions in accordance with the present invention exhibit little deterioration in performance versus conventional diesel fuels.

The diesel fuel composition in accordance with the present invention comprises and shall be understood to mean a mixture of hydrocarbon that is the fraction of crude oil that distills after kerosene and is useful in combustion in diesel type or compression-ignition engines. This diesel fuel may include No. 1-D and No. 2-D grade diesel fuels, as designated by ASTM standards. Also, as is known in the art, diesel fuel may comprise atmospheric or vacuum distillate or blends thereof. The diesel fuels will have a cetane number greater than 40 and generally possess 0.20% by weight or less of sulfur.

The utilization of triglycerides of a vegetable oil provides a diesel fuel composition which may be prepared from natural and renewable sources. The triglyceride of a vegetable oil is selected from a group comprising rapeseed oil, soybean oil, peanut oil, palm oil, palm kernel oil, coconut oil, tall oil, canola oil, linseed oil, corn oil, sesame oil, cottonseed oil, jatropha oil, crab oil, sunflower seed oil, safflower oil, oleo safflower oil, triolean and mixtures thereof.

The oxygenate material utilized in the present invention facilitates oxidation of the fuel oil composition is preferably an alcohol selected from a group comprising n-butanol or n-octanol.

The fuel oil composition in accordance with the present invention includes an oxygenate material ranging between 0.1 to 30% by weight with respect to concentration of triglycerides of the vegetable oil. The oxygenate is added to the fuel composition to control and limit the exhaust emissions from the combustion process of the fuel composition, lower viscosity and improve winterization properties. The oxygenate material possesses a flash point or a minimum temperature that enables combustion to take place of at least 38° C., a pour point of at least 15° C., and a solidification of less than 20° C. The oxygenate material may be selected from a group comprising n-butanol, n-hexanol, n-heptanol, n-octanol, n-nonanol or n-decanol, a ketone, such as, 2-ocatanone and long chain fatty acid esters, such as, methyl cis-9-octadecenoate.

Further, in accordance with the present invention, the diesel fuel composition may further include and be comprised of 0.01-7% by weight with respect to the weight concentration of the triglycerides of the vegetable oil of a monocyclic terpene material. The preferred terpene material is limonene and is utilized in the present invention to facilitate dispersion of the fuel oil composition, to improve lubricity of the fuel and to satisfy winterization of the fuel oil composition.

The diesel fuel composition in accordance with the present invention provides a renewable non-petroleum source of non-toxic materials for use in a diesel fuel composition. A typical preferred range of this renewable source provides lubricity, winterization protection, and controls pollutant emissions while maintaining engine performance.

The following examples serve to illustrate the scope of the fuel oil composition in accordance with the present invention.

EXAMPLE 1

To a 80% by weight D-2 grade diesel fuel was added 16% by weight of a vegetable oil (soybean oil), 4.0% by weight of an oxygenate material (n-octanol) with respect to the weight of the soybean oil. The fuel composition was mixed and stirred to provide a uniform fuel.

EXAMPLE 2

To a 95% by weight D-2 grade diesel fuel was added 4% by weight of a vegetable oil (soybean oil), 1.0% by weight of an oxygenate material (n-octanol) with respect to the weight of the soybean oil. The fuel composition was mixed and stirred to provide a uniform fuel.

EXAMPLE 3

To a 95% by weight D-2 grade diesel fuel was added 4% by weight of a vegetable oil (soybean oil), 1.0% by weight of an oxygenate material (n-butanol) with respect to the weight of the soybean oil. The fuel composition was mixed and stirred to provide a uniform fuel.

EXAMPLE 4

To a 95% by weight D-2 grade diesel fuel was added 4% by weight of a vegetable oil (soybean oil) 0.75% by weight of an oxygenate material with respect to the weight of the vegetable oil, and 0.25% by weight of a terpenoid material (limonene) with respect to the weight of the soybean oil. The fuel composition was mixed and stirred to provide a uniform fuel.

EXAMPLE 5

To a 95% by weight D-2 grade diesel fuel was added 5% by weight of a vegetable oil (soybean oil). The fuel composition was mixed and stirred to provide a uniform fuel.

The lubricity evaluation of Examples 1 and 2 were conducted at 60° C. utilizing the High Frequency Reciprocating Rig (HFRR) test described in ASTM method D6079-97. The average Wear Scar Diameter (WSD) is calculated by the equation

${WSD} = \frac{\left( {M + N} \right)}{2}$

where WSD is the average wear scar diameter in mm, M is the major axis in mm and N is the minor axis in mm.

Table I summarizes the various test results for D-2 grade diesel fuel, and for Examples 1-5 as set forth above.

TABLE I Property Diesel 1 Diesel 2 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Flashpoint NA  66.7 48.9 63.9 45.0 53.9 66.1 ° C. Viscosity NA NA 3.74 NA 2.67 2.67 2.89 cSt Lubricity 671* 536* 325 331 NA NA NA HFRR@ 60° C. Cetane NA NA 45.2 NA 42.6 43.2 NA Sulfur NA 361 288 NA 41 42 NA ppm Cloudpoint NA  −6 −8 NA NA NA NA ° F. *literature values

The present invention has been found to provide a reduction in engine emissions, increased lubricity and improved winterization. The reduction in engine emissions is directly related to the reduction in sulfur content of the fuel without injection system or nozzle wear and without deterioration of engine performance.

While particular embodiments of the present invention have been described, it will be obvious to those skilled in the relevant art that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the appended claims are to cover all such changes and modifications as fall within the spirit and scope of the present invention. The matter set forth in the foregoing description is offered by way of illustration only and not as a limitation. 

1. A diesel fuel composition comprising: 50-99.9% by weight diesel fuel; 0.1 to 50% by weight of triglycerides of a vegetable oil; and 0.1 to 30% by weight with respect to the weight concentration of triglycerides of a vegetable oil of an oxygenate; wherein said oxygenate is present in the diesel fuel composition in an amount effective for said composition to exist as a stable solution and the combined amounts of oxygenate, and triglycerides of said vegetable oil are sufficient to impart to said composition a kinematic viscosity in the range of 1.5-4.1 centistokes of 40° C.
 2. The diesel fuel in accordance with claim 1, further comprising 0-7% by weight with respect to the total weight concentration of said triglycerides of a vegetable oil of a terpenoid.
 3. The diesel fuel in accordance with claim 1, wherein said triglycerides of a vegetable oil are selected from a group comprising rapeseed oil, soybean oil, peanut oil, palm oil, palm kernel oil, coconut oil, tall oil, canola oil, linseed oil, corn oil, sesame oil, cottonseed oil, jatropha oil, crab oil, sunflower seed oil, safflower oil, high oleic safflower, and triolein.
 4. The diesel fuel in accordance with claim 1, wherein said triglycerides of a vegetable oil is soybean oil.
 5. The diesel fuel in accordance with claim 1, wherein said oxygenate has a flashpoint of more than 38° C.
 6. The diesel fuel in accordance with claim 5, wherein the oxygenate is selected from a group comprising n-butanol, n-hexanol, n-heptanol, n-octanol, n-nonanol or n-decanol, a ketone, such as, 2-ocatanone and long chain fatty acid ester, such as, methyl cis-9-octadecenoate.
 7. The diesel fuel in accordance with claim 5, wherein said oxygenate is n-butanol.
 8. The diesel fuel in accordance with claim 5, wherein said oxygenate is n-octanol.
 9. The diesel fuel in accordance with claim 2, wherein said terpenoid is limonene.
 10. A process of improving the lubricity of diesel fuel having 500 ppm or less sulfur comprising: adding 0.1 to 50% by weight triglycerides of a vegetable origin to the diesel fuel; adding 0.1 to 30% by weight with respect to the weight concentration of triglycerides of an oxygenate to the diesel fuel; and adding 0.01 to 0.7% by weight with respect to the weight concentration of the triglycerides of a terpene to the diesel fuel.
 11. The process in accordance with claim 10 wherein the sulfur content of the diesel fuel is less than 50 ppm by weight.
 12. A fuel lubricity additive compound, comprising a triglyceride of a vegetable origin and an oxygenate material. 